HC08 monitor mode using SWI

Vtst level is sampled during hardware reset and based on this the chip is put into normal or monitor mode.

That's exactly how it SHOULD work.

Cool. So why does the manual say you can execute an SWI to get into monitor mode? What's an SWI got to do with the Vtst/hardware reset combo? I'm a bit confused.

Thanks, Anna

I have not used to HC08, but for the SWI to work, you would need to have the interrupt routine for the SWI do the processing to enter the monitor at the appropriate entry point. Since SWI is often used by monitors for breakpoints, the code there would normally save some machine state, determine whether a breakpoint had been encountered (by comparing the SWI with its breakpoint list), and starting monitor code. Check the monitor documentation wrt SWI.

Thad

If the SWI-vector address is _programmed_ (by you) with the address of the on-chip monitor, then you should get what you want.

The manual may be referring to 'user-access monitor' operation: see Motorola application-note AN2305. This is a handy lash-up that sacrifices a few pins and the SWI for the gift of not having to read all that confusing monitor-entry stuff over and over, as well as seamless debugging with P&E tools (and others?) Wade Hassler